You can view your purchase history by following these steps:
On your mobile device (iPhone/iPad):
- Go to Settings
- Tap on your Apple ID, at the top
- Tap Media & Purchases, then tap View Account
- In the Account window, tap Purchase history
On your computer:
- Open iTunes on your computer
- Click "Account" and log in (or confirm the email address)
- Click "View my account..."
- Scroll down to "Purchase History" and click "See All"